One of the problems faced by the perfume industry lies in the relatively rapid loss of the olfactive benefit provided by odoriferous compounds as a result of their volatility, particularly that of “top-notes”. Also, some fragrance ingredients can be unstable in applications of functional perfumery and get lost due to degradation or to rapid evaporation.
In particular, most commonly used ingredients for imparting vanilla-type odor notes such as vanillin (4-hydroxy-3-methoxybenzaldehyde) and ethyl vanillin (3-ethoxy-4-hydroxybenzaldehyde) are known to rapidly decompose in challenging medium such as consumer product bases and to lead to the coloration of the products. Thus, there is a need for providing them in an encapsulated form not only to protect them but also in order to deliver long lasting vanilla notes in challenging medium such as consumer product bases. However, those ingredients cannot be encapsulated in a classical way at a sufficient loading to provide satisfactory effect from an odor perspective at a reasonable cost. Furthermore, when encapsulated, vanillin and ethyl vanillin are known to have a particular tendency to diffuse through the shell of microcapsules especially when added to consumer products which contains surface active ingredients.
In WO2014059087, these issues have been tackled. As a proposed solution for providing vanillin in an encapsulated form, core-shell microcapsules are described as being formed by combining vanillin and/or ethyl vanillin with a preformed core-shell microcapsule slurry or formulation and then aging the mixture for a time sufficient for vanillin and/or ethyl vanillin and microcapsules to interact. However, this process presents the drawback of requiring an extra step compared to standard encapsulation and implies that the shell of microcapsules comprising vanillin and/or ethyl vanillin as described in this application is permeable. So this process does not allow obtaining microcapsules with a controllable final amount of vanillin and/or ethyl vanillin inside the core of the capsule and the diffusion upon storage in challenging medium is not prevented. Furthermore, this process does not allow encapsulating large amounts vanillin and/or ethyl vanillin as the majority of these ingredients actually stay in the slurry as shown in the experimental part below.
There is therefore still a need to provide microcapsules susceptible of imparting a vanilla odor note when needed, having a high and controllable loading of perfuming compound responsible of the vanilla-based note inside the core of the microcapsules, using straightforward encapsulation process and without being limiting to permeable shells only.
The present invention provides a solution to the above mentioned problem with microcapsules comprising high loadings of a compound of formula (I) as defined above as part of a perfume oil in the core and comprising a shell with a permeability that can be chosen as a function of use and desired effect of the microcapsules. The compounds of formula (I) have been reported in WO2011132098 as perfuming ingredients conferring an odor of sweet vanilla type very close to the odor of vanillin, but were not expected to be possibly encapsulated at particularly high loadings, to impart an intense note and to circumvent stability issue in aggressive medium of capsules based on vanillin and ethyl vanillin.